The present invention relates generally to a method and apparatus for draining fluid from a body cavity, and more particularly to a catheter and a method for using the catheter to drain urine from the bladder.
Catheters have been used for centuries to drain fluid from a body cavity, e.g., to drain urine from the bladder. Modern catheters typically include a long narrow tube with a retention device and drainage port disposed at one end and an exit port at the other end. After a medical practitioner inserts the retention end of a catheter into the bladder, the retention device is deployed to hold the catheter in place while urine drains from the drainage port to the exit port.
Conventional retention devices include Malecot wings and balloons, such as those used in the Foley catheter. Catheters with balloon retention devices are inserted into the bladder in a deflated state until the balloon retention device passes through the bladder neck and into the bladder. Once the balloon retention device passes through the bladder neck and resides within the bladder, the medical practitioner inflates the balloon with a fluid. The inflated balloon retains the upper portion of the catheter, including the drainage port in the bladder. Because the balloon essentially blocks the opening in the bladder, the drainage port for draining fluids is typically located above the retention balloon. To release the catheter, the medical practitioner deflates the balloon by withdrawing the fluid from the balloon.
Catheters with Malecot wings normally assume a deployed orientation. Therefore, before catheters with Malecot wings are inserted into the bladder, the Malecot wings must be collapsed. This is accomplished by inserting an external device, i.e., a trocar, to apply pressure to the Malecot wings and force them into a collapsed orientation. After the wings pass through the bladder neck and into the bladder, releasing the pressure, e.g., by removing the trocar, deploys the wings. The deployed wings hold the catheter in place while the urine drains from the bladder. To release the Malecot catheter, the medical practitioner reapplies pressure to the wings by reinserting the trocar to collapse the Malecot wings while the catheter is withdrawn.
Catheters utilizing the above described retention devices have encountered numerous problems over the years. For example, the catheter must include an inflation channel and/or external means for deploying the retention device, which complicates the catheter design and the catheter administration procedure. In addition, when the drainage port is disposed above the retention device, the medical practitioner may begin deploying the retention device while the retention device is still at least partially in the urethra, which may be uncomfortable for the patient. Further, because there is no way for the medical practitioner to know that the retention device is fully collapsed, the medical practitioner may begin removing the catheter from the bladder before the retention device is fully collapsed, which may also cause discomfort to the patient.